igh-risk sexual behaviors are those practices that increase the risk of acquiring a sexually transmit­ted infection. Following are some of these high-risk behaviors. Drinking alcohol and engaging in sexual activity under the influence of alcohol often increases the risk of ac­quiring an STI because alcohol can increase the likelihood that a person will participate in high-risk sexual activity.

Engaging in safer-sex behaviors can decrease the risk of acquiring an STI. Safer sex behaviors include knowing your partner’s STI history, being in a monogamous sexual rela­tionship, using condoms and barriers for all sexual activity, and avoiding alcohol use (see Chapter 10, Sex in Real Life, "Safer-Sex Behavior Guidelines," on page 323).

• Unprotected sexual intercourse without the use of a male or female condom unless this occurs in a long-term, single­partner, monogamous relationship in which both partners have been tested for STIs

• Engaging in oral sex with a male or female partner with­out using a condom or dental dam unless this occurs in a

long-term, single-partner, monogamous relationship in which both partners have been tested for STIs

• Engaging in sexual intercourse prior to age 18

• Having multiple sex partners

• Engaging in sexual intercourse with a partner who has multiple sex partners

• Engaging in anal sex without a condom

• Engaging in sexual activity with a partner who has anal sex with multiple sex partners

• Engaging in oral sex with a partner who has multiple sex partners

• Engaging in sexual activity with a partner who has ever injected drugs

• Engaging in sex work or sexual activity with a partner who has ever engaged in sex work

• Engaging in sexual activity with a partner who has a his­tory of STIs

• Engaging in sexual activity with a partner with an un­known STI history

haviors that put them at risk, such as having multiple partners and not always using condoms (see the accompanying Sex in Real Life, “High-Risk Sexual Behaviors,” for more information).

Подпись:The truth is that young adults are disproportionately affected by STIs, and the in­cidence of STIs continues to grow in this population (vonSadovszky et al., 2002). Studies have found 40% of sexually active young women have had an STI (Bunnell et al., 1999) and two-thirds of all STIs occurred in individuals under 25 years old (Hatcher et al., 2004). More frightening still is that adolescents are more biologically at risk for developing an STI (Santelli et al., 1999). Research has found that the cervix of a teenage girl is more vulnerable to certain STIs than the cervix of an adult woman (Centers for Disease Control and Prevention, 2005d). Even so, adolescent females of­ten do not believe they are at risk for contracting a sexually transmitted infection (Ethier et al., 2003).

High-Risk Sexual BehaviorsQuestion: How did STIs start? I have heard it was from having sex with animals. Is this true?

Everyone has different theories on how STIs started. Some claim that it was a punishment for being sexually active; others thought that it was a result of promiscuity. We know that sexually transmitted infec­tions are caused by bacteria and viruses. A person who comes into contact with these bacteria and viruses is at risk of developing an STI. We do not know where these different infectious agents came from, just as we do not know where the common cold virus or the flu originated.